1. Field of the Invention
The present invention relates to methods for controlling the operation of an air conditioning system, and, more particularly, to a method for controlling the operation of an air conditioning system, in which the air conditioning system can be quickly stabilized, after starting, into a regular operation.
2. Background of the Related Art
In general, the air conditioner adjusts temperature, humidity, air flow, cleanliness of air, and etc., in a particular area suitable to purposes of use, such as cooling or heating room spaces, like residing spaces, restaurants, library, or offices, with a compressor and heat exchangers, and circulating refrigerant therethrough.
A related art inverter air conditioner and a method for controlling the operation of the same will be described, and problems related thereto will be discussed.
The related art inverter air conditioner is provided with a compressor, an outdoor heat exchanger serving as a condenser, an indoor heat exchanger serving as an evaporator, an expansion device between the outdoor heat exchanger and the indoor heat exchanger, pipelines connected between the parts, and a microprocessor (not shown) for progressing a refrigerating cycle of the inverter air conditioner with reference to a preset room cooling temperature, an outdoor temperature, and a room temperature.
The expansion device may be a capillary tube, an electronic Thermal Expansion Valve (TXV), or a Linear Expansion Valve (LEV). In the case of the inverter air conditioner, since an operative frequency varies from a low frequency range to a high frequency range, the LEV is employed mostly, rather than the capillary tube that has a limitation in a control range of a refrigerant flow rate.
A related art method for controlling operation of an inverter air conditioner will be described.
The related art method for controlling operation of an inverter air conditioner is provided with a starting operation step in which the air conditioner is operated while an operative frequency of a compressor is increased from, substantially, 0 Hz to a preset target frequency, and a regular operation step in which the inverter air conditioner is operated while keeping the target frequency after finish of the starting operation step, i.e., the compressor reaches to the target frequency.
In the starting operation step, the LEV expands refrigerant passed through the condenser in a state the LEV is opened to a preset portion.
When the compressor reaches to the target frequency, it is required that the inverter air conditioner enters into the regular operation step. However, when the compressor reaches to the target frequency, a degree of superheat of the refrigerant at an outlet of the compressor is not adequate for cooling the room. The degree of superheat of the refrigerant at an outlet of the compressor represents a value a pipeline temperature of the condenser is subtracted from a temperature of the refrigerant discharged from the compressor.
For elevating the degree of superheat of the refrigerant at an outlet of the compressor to an appropriate level, the LEV is opened smaller for a preset time period. However, in the process, the degree of superheat of the refrigerant at an outlet of the compressor can become excessive, i.e., overshoot.
Consequently, the related art method for controlling operation of the inverter air conditioner has the following problem.
If the degree of superheat of the refrigerant at an outlet of the compressor is excessive, the system becomes unstable, and for stabilizing the system again a certain time is required, and much power is consumed.
In order to cope with the problem, it is required to develop a method for controlling operation of an inverter air conditioner, which can prevent a system instability from taking place in a process the inverter air conditioner enters into the regular operation step through the starting operation step when the frequency of the compressor reaches to the target frequency.